1. Field of the Invention
This invention relates to a check valve for use primarily, but not essentially, in a toilet assembly particularly, but not necessarily, of the type installed in land or water recreational vehicles, for example motorhomes or boats respectively.
2. Brief Description of the Prior Art
A requirement of a check valve of the type with which this invention is concerned provided in an assembly, is to open to allow passage of waste material and thereafter to close to prevent re-entry of waste material or of any smell or gases deriving from such waste material. It has been proposed heretofore that such a check valve be a duckbill valve having a body of elastomeric material having a tubular inlet portion at a first end with a radial flange and a circumferential shoulder, the body having opposed side walls tapering towards each other to terminate in sealing edges at a second end, opposite to the first end. The sealing edges lie in a plane diametrical of the tubular inlet portion. A duckbill valve of this type is disclosed in U.S. Pat. No. 5,063,619.
A problem with such duckbill valves is the limitations on the quantity and diametrical size of material that can pass through the mouth of the valve when open by deflection apart of the sealing edges during a xe2x80x98flushingxe2x80x99 operation.
An object of the present invention is to provide a check valve in which such problem is obviated or mitigated.
Accordingly, the present invention is a check valve comprising a body of elastomeric material having a tubular inlet at a first end with a radial flange, the body having a side surround with three equi-spaced valleys tapering towards a second end opposite to the first end and having thereat sealing edges in the form of a triskelion, whereby an openable mouth is extendible between said sealing edges of substantially the same areal or cross sectional dimensions as the tubular inlet.
Preferably, each arm of the triskelion is of the same length and has a slit substantially median of its width, and the slits in the arms unite together at adjacent ends.
Preferably also, the wall thickness of the valley sides is greater than the wall thickness of the side surround. At the bottom of each valley, a groove is beneficially positioned to provide a flexing line. The wall thickness of the bottom of the groove is desirably less than the wall thickness of the valley sides.